Use these options to specify how the date range returns results. "Exact" means that the start and end dates of descriptions returned must fall entirely within the date range entered. "Overlapping" means that any description whose start or end dates touch or overlap the target date range will be returned.

Originally this series covered various types of correspondence, from private letters to memoranda addressed to delegations or to other NATO bodies. In the early 1970's a new series (SG) was created to cover personal communications by the Secretary General, and it was decided that PO memoranda would be used for formal documents addressed to Permanent Representatives for information or decision regarding the work of the Council. P...